Floor conveyor with an assistance device

Description

[0001] The present invention relates to a forklift truck equipped with a drive unit and a load unit, the load unit having a height-adjustable load-bearing element. Furthermore, the forklift truck has an assistance device.

[0002] Industrial trucks with driver assistance systems are well-known and increasingly used. These systems are usually designed for one or more precisely defined vehicle tasks or functions. They can perform these functions automatically or assist the driver.

[0003] Especially with the use of partially or fully autonomous vehicles, AGVs (Automated Guided Vehicles), assistance systems are of particular importance. Autonomous vehicles move independently in space, relying on fixed, spatially unchanging reference points for their orientation.

[0004] From CN 203 411 297 U, an electric forklift truck with hydraulic operation is disclosed. A radar sensor is used to control the vehicle. This sensor detects the distance beneath the height-adjustable load-bearing device, for example, the distance to a shelf when setting down a load. This distance measurement controls the hydraulic lifting mechanism to prevent excessive downward force during lowering.

[0005] German patent DE 10 2004 047 209 A1 discloses a security monitoring system for transport vehicles. This system monitors an area around the transport vehicle. A field of view is defined for the vehicle, within which a 3D measurement is performed.

[0006] WO 2004 / 0 44 609 A1 discloses a method and system for material transport in which radar is used. In this system, the vehicle orients itself using stationary sensors that reflect an incoming beam, thus enabling the vehicle to orient itself in space by taking into account the angle of the reflected beam.

[0007] US patent 2016 / 138247 A1 discloses a work machine that uses radar to assist the driver. The system provides the user with information regarding the current position of a component that is not visible to the driver. For picking up pallets with a load-bearing device, image processing is proposed in which the trajectories of the fork tips are determined depending on the steering angle.

[0008] From WO 2018 / 194765 A1, a method and system for the detection, recognition, and localization of pallets is known. The system is based on image analysis of the edges. Radar is additionally used to potentially detect further pallets.

[0009] US patent 2018 / 120465 A1 discloses a forklift truck that has two proximity sensors at the tips of its load arms. These proximity sensors are further supported by additional proximity sensors arranged along the load arms.

[0010] Furthermore, document EP1408001A1 discloses a forklift truck with the features of the preamble of claim 1.

[0011] The invention is based on the objective of providing a forklift truck that can determine a relative position between the load-bearing element and the load or storage position using simple means.

[0012] According to the invention, the problem is solved by a forklift truck with the features of claim 1. Advantageous embodiments are the subject matter of the dependent claims.

[0013] The industrial truck according to the invention is equipped with a drive unit and a load unit. The load unit has a height-adjustable load-bearing element. This load-bearing element can be designed for low-lift or high-lift operation. At least one radar sensor is provided on the height-adjustable load-bearing element, which is directed towards a load to be picked up, i.e., in an area in front of the load-bearing element. The radar sensor detects a multitude of distances to the load to be picked up. A relative position of the load-bearing element and the load to be picked up is determined from the detected distances and made available to an assistance device. This concept, formulated for load picking, also applies according to the invention to the placement of a load. Here, too, at least one radar sensor is provided on the load-bearing element, which is directed towards a storage position. A multitude of distances to the storage position are detected by the radar sensor.From the measured distances, a relative position of the load-bearing device and the bearing position is determined and transmitted to an assistance system. The essential concept of the inventive method is that a radar sensor is used to monitor the area in front of the load-bearing device and to measure distances to the load to be lifted and / or a bearing position for the assistance system. This enables a reliable relative position determination of the load-bearing device to the load to be lifted and / or the bearing position, thus allowing for precise handling of the load. Regarding the assistance system, it should be noted that it can be designed for either load lifting or load release; naturally, the assistance system can also use the determined relative positions during both load lifting and load release.In a preferred embodiment, the drive unit is equipped with controls for the load-bearing device and the industrial truck. The assistance device is designed as a display-based assistance device. In this embodiment, the relative position of the controls is displayed to the operator. A display corresponding to the controls allows a function to be performed in a specific direction R using a control, with the assistance device showing a corresponding representation for R or for actuating the control in the direction R. For example, if the load-bearing device has controls for up, down, right, and left, the display of the assistance device shows arrows indicating up, down, right, and left, showing how the controls must be actuated to achieve the desired position.Such a load indicator device can be advantageously used both when picking up the load and when setting down the load in the storage position.

[0014] In a preferred advanced training program, the assistance device is configured as a semi-automated assistance device. Semi-automated assistance exists when the load-bearing device and / or the industrial truck as a whole are controlled by the assistance device for load picking up or dropping off as soon as the operator activates the corresponding release control. In this semi-automated operation, the activation of the control only triggers a release, and the precise control of the control is handled by the semi-automated assistance device; for example, the operator releases the function via the control, and the semi-automated control then controls the lifting or lowering function in terms of height, speed, acceleration, etc.Additionally, the semi-automated assistance system can be configured to interrupt manual operation of the control element when a load can be picked up or set down. The semi-automated assistance system thus monitors the operator's control and intervenes if there is a risk of manual override. Interrupting operation includes situations where, as the target position is approached, the operating speed is adjusted, for example, by decreasing or increasing it while the control element is still being operated.

[0015] Furthermore, the semi-automated assistance system can be configured to limit manually operated controls to a maximum value, while allowing the operator to freely control smaller values. This enables the operator to control the system more slowly, for example in complex situations, than would be possible for the semi-automated assistance system itself. This slower control is advantageous for both loading and unloading operations.

[0016] In a further embodiment of the semi-automated assistance system, it is designed to select the speed of the control signal from a non-proportionally controlled operating element, such as one with only an on and off state, according to the relative position. A non-proportionally controlled operating element is, for example, a push button or a switch, such as a toggle, rotary, or slide switch. The semi-automated operation then ensures that the speed and / or acceleration with which an actuation of the non-proportionally controlled operating element is implemented corresponds to the detected relative position between the load-bearing device and the load or storage position.

[0017] In a further preferred embodiment, the assistance device is designed as an automated assistance device. The automated assistance device controls the load-bearing device and / or the industrial truck as a whole for picking up or setting down a load, unless the operator interrupts the automatic operation. Depending on the relative position, automatic operation requires that the load-bearing device, for example, be controlled for lifting and lowering, and that the industrial truck as a whole be controlled, for example, for aligning the load-bearing device.

[0018] In a particularly preferred embodiment, the system comprises a self-propelled industrial truck that is controlled according to its position in space, particularly in terms of direction and speed. The assistance system intervenes to correct the automatic control for load picking. The existing spatial control of the self-propelled industrial truck is supplemented by an automatic control system that additionally utilizes relative position for improved orientation. This allows the self-propelled vehicle to navigate even in environments containing numerous obstacles not represented in a spatial representation.

[0019] The invention is explained in more detail using the example of a self-propelled industrial truck. The following are shown: Fig. 1 a schematic side view of an autonomously driving vehicle, Fig. 2 a perspective detail view of a storage process and Fig. 3 a perspective detail view of a storage process.

[0020] Fig. 1 Figure 10 shows a self-propelled industrial truck 10, which has a drive unit 12 and a load unit 14. The load unit 14 has a lifting mast 16 on which a load fork 18 is height-adjustable. The load unit 14 also has wheel arms 20 with which the vehicle stabilizes itself. A communication device 22 is also provided on the load unit 14, through which the vehicle communicates with a higher-level control system. Signals regarding travel commands, the position and status of the vehicle and the goods, as well as other aspects important for operation, can be exchanged via the higher-level control system (not shown).

[0021] The drive unit 12 has a schematically represented control unit 24, via which an operator standing at the vehicle can perform the control or intervene in it in the case of a partially or fully automated control.

[0022] A radar sensor 26 is provided on the load-bearing device 18, which detects distance values ​​in direction A. The radar sensor 26 is preferably a millimeter-wave radar sensor, whose radar waves can resolve even fine structures on the order of centimeters. This fine resolution provided by the millimeter-wave radar sensor offers particular advantages for relative position determination, as the relative position of the load to the load-bearing device can also be detected. For example, if a pallet is in an inclined position relative to the longitudinal extension of the load forks, the fine resolution of millimeter waves from the radar sensor allows this angle to be detected and compensated for by controlling the entire vehicle.

[0023] Fig. 2Figure 1 shows, for example, in a semi-perspective view how the millimeter-wave radar sensor 26 detects a pallet 28 with its distance measurement and determines the position of the opening 30 from the detected distance values. The fork tine 18a can thus be controlled in its position relative to the receiving opening 30.

[0024] Fig. 3 Figure 28 shows a similar situation during the storage of a pallet. The millimeter-wave radar sensor 26 detects a lateral restriction imposed by a vertical rack support during storage. The second millimeter-wave radar sensor, located on the other fork tine 18b, detects a lateral limit 32 imposed by an already stored pallet during the storage process. In this way, a relative position can be provided to an assistance system during pallet storage, enabling safe and reliable storage.

[0025] The measurements acquired by the radar sensors 26 are represented as a point cloud. This point cloud, with its points, is analyzed to determine the relative position of the load-handling device to the load-handling aid or to the load itself. The relative position is stored, for example, in Cartesian coordinates; additionally, the orientation of the load relative to the vehicle can be determined. This information is processed by the assistance system.

[0026] A display assistance system provides the driver with information about the position of the forks of the load-handling attachment relative to the load via a display. The information can, for example, indicate the necessary position correction using arrows. Correction suggestions regarding the forklift's orientation can also be provided, such as steering direction or an arrow indicating the direction of rotation of the vehicle's rear. Other graphical visualizations are also possible. The display assistance system can also emit acoustic signals, particularly to confirm that the forks have reached the target position.

[0027] In semi-automated operation, the positioning of the forks and / or the alignment of the vehicle's rear are performed by the assistance system. The user must always hold down a control element to activate the action. Preferably, the control element to be operated is assigned to the function that is enabled for semi-automatic operation when it is pressed. A form of semi-automation occurs, for example, when the user activates the mast lift and the assistance system intervenes to limit the lift to the target height. Similarly, lateral thrust could also be controlled semi-automatically. In these cases, a combination with indicator functionality, such as arrows to guide the operator, would be beneficial to ensure the user operates the controls in the correct direction.

[0028] Partial automation is also possible by using a selected control element, where a distinction is made between proportional and non-proportional controls. In the case of a proportional control element, the assistance system limits the maximum speed proportionally to the movement of the control element. This allows the user performing the operation to act safely in complex situations. If the assistance function is provided by a non-proportionally controlled element, such as a button, switch, or slider, the assistance system specifies the speed and / or acceleration at which the control element's function is executed. Releasing the non-proportional control element interrupts its operation.

[0029] When a fully automated assistance system is present, two scenarios can be distinguished: In the first scenario, the assistance system temporarily and / or locally takes over control of the vehicle. In the second scenario, the fully automated assistance system intervenes in an absolute warehouse navigation system that uses spatially fixed reference points for control. This means that the fully automated assistance system provides a correction parameter that is used to compensate for offsets caused, for example, by inaccurate vehicle localization, inaccurate pallet positioning, uneven surfaces, and other unforeseen factors. This makes the entire system more robust. Reference symbol list

[0030] 10 Forklift 12 Drive unit 14 Load unit 16 Lifting mast 18 Load fork 18a Fork tine 18 Fork tine 20 Wheel arms 22 Communication unit 24 Control unit 26 Radar sensor 28 Pallet 30 Opening 32 Limit

Claims

1. Industrial truck (10) with a drive part (12), a load part (14) which is equipped with a heightadjustable load-carrying means, and an indicating assistance device, wherein the drive part (12) comprises control elements for the load-carrying means and the industrial truck (10) as a whole, characterized in that at least one radar sensor (26) is provided on the load-carrying means, which is directed at a load to be picked up or at a storage position and detects a plurality of distances thereto, wherein a position of the load-carrying means relative to the load to be picked up or storage position is determined from the detected distances and is made available to the indicating assistance device, and that the indicating assistance device is configured to display the relative position to an operator in a representation corresponding to the control elements, wherein if a function is to be executed in a specific direction (R) with the control element, the assistance device displays in its representation a corresponding representation for the actuation of the control element in direction (R).

2. Industrial truck (10) according to Claim 1, characterized in that the assistance device is configured as a semi-automated assistance device, which controls the load-carrying means and / or the industrial truck as a whole for a load pickup and / or for a load set-down when the operator actuates the corresponding control element for release.

3. Industrial truck (10) according to Claim 2, characterized in that the semi-automated assistance device is configured to interrupt a manually actuated operation when a load pickup and / or load set-down can take place.

4. Industrial truck (10) according to Claim 2 or 3, characterized in that the semi-automated assistance device is configured to limit the manually actuated operation to a maximum value, wherein the operator can select deviating, smaller values therefrom.

5. Industrial truck (10) according to one of Claims 2 to 4, characterized in that the semi-automated assistance device is configured, in the case of a non-proportionally controllable control element, such that the speed and / or acceleration of the control specified by the control element is selected according to the relative position.

6. Industrial truck (10) according to one of Claims 1 to 5, characterized in that the assistance device is configured as an automated assistance device, which completely controls the load-carrying means and / or the industrial truck as a whole for a load pickup and / or a load set-down if the operator does not terminate the automatic operation.

7. Industrial truck (10) according to Claim 6, characterized in that it is a self-propelled industrial truck which is controlled according to its position in space, wherein the automatic assistance device intervenes correctively in the automatic control for a load pickup and / or load set-down.